I seen it mentioned in another thread. This will obviously help with leading of non-gas checked cast bulets but does it adversly affect accuracy? What kind of effect does it have on pressure?

Shooting the Inverted Gas Check
by Forrest

This past shooting season has been an enjoyable one for me. Our editor has encouraged me to write about the upside-down gas check idea which I have tried in my buffalo rifle with interesting and encouraging results.

My rifle of choice this summer has been a Falling Block Works �J� action barreled up in 44/63 Ballard. I like this designation better than the better known 444 Marlin since I shoot mainly in the �traditional� matches but it is in fact the 444 chambered on a 16 twist barrel.

In the process of load development I settled on a custom made, lathe bored 460 grain Mos bullet, 19 grains SR 4759, � sheet T/P and an unsized, inverted, Hornady gas check as �standard�.

The inverted gas check idea came from CBA member and my correspondent Mustafa Curtess. In one letter Mustafa told me how he had been trying the inverted gas checks (IGC) in his 45/70 with good results. I loaded some up in the 44/63 and tried them out too. My results were very good and I have continued to shoot this combination for all plain base bullet rifle shooting ever since.

Since this is a rather unusual utilization of a gas check I'll explain how I put them to use: The 44/63 case, being a straight sided design, allows me to seat the unsized IGC under the bullet without running the risk of a check dropping off, as might be possible in a bottle necked case. I start each check into the lightly expanded case mouth about 0.060� by using a backed-off case expander punch. The IGC is then forced down as the bullet is seated on top of it, slightly compressing the column of powder and T/P filler. The procedure prevents the check from moving away from the base of the bullet during handling and transport. This tight stacking of components is very important in my view because if the check were to move away from the bullet base it would then become a projectile inside the case upon firing. When it hit the base of a stationary bullet pressures would instantaneously rise, exceed the strength of the barrel steel and ring the chamber. I caution any member who contemplates trying this loading method to use the utmost caution!

As an experiment concerning the (however remote) possibility of a check or filler becoming loose or improperly placed in the case I have disassembled loaded cartridges to see what happens during the final seating procedure. After the bullet was pulled from the loaded cartridge I found that the check was so firmly wedged in the case that it was destroyed during the removal process: It was certainly in no danger of moving short of actual discharge of the round! Under the check the T/P filler was lightly compressed. This was only to the degree that the powder charge was firmly held in place, never even close to any crushing amount of pressure.

From my point of view the IGC serves three purposes: It does seal the hot powder gases just as well as a normally seated check and certainly better than a card wad does. During firing the check also scrapes the bore, removing any lead wash which might otherwise accumulate during the firing of plain base bullets. Then, I believe that the unsized check, being forced into the case ahead of the soft lead bullet, acts like an expander punch, opening the case just a bit more and reducing the amount of bullet deformation I have seen on bullet bodies which were forced into undersize cases. (My cases are only partially sized, but excess case neck tension is something we all know should be controlled to a bare minimum.)

I have used this load for shooting matches and for everyday sessions at my range here in Wyoming. Excellent consistent results have been my experience. In loading the IGC in my 45/70 I have found that any of the loads where I formerly used a 0.050 card wad and filler under the bullet permit the use of a IGC without changing the load�s former dependability at all and improving accuracy as noted above. The advantages of not having to be concerned about lead fouling are considerable, both because it no longer happens, and because worry itself is eliminated. In all cases, accuracy is improved.

Once I get my chrony fixed I'll have to try some of my known good loads in my 480 w/ plain base bullets, and compare accuracy and velocity between the plainbase and plainbase +inverted check to see the effects on velocity and accuracy.

The main reason I wanted to try the inverted check was to allow me to use existing plainbase bullets at higher speeds w/o the added expense of having a new mold cut.

That is what i am lookin at Paul. I am not casting but am buyin bullets and startin to get some leading once i get velocities where i want em. I think that i am gonna purchase some gas checks and give it a go meself. Appears that Lyman is the only one that offers .410" checks.....

Good topic...I have a pair of nearly full 1K count boxes of .44 and .45 caliber GC's. Don't know how I got them...but looks like I'll be experimenting with them!!

I have been playing with the igc too and have also to add,make sure that the bullet bases are clean,that way the checks don`t fall off at irregular intervals.this was a slight problem for me at first as I was using a liquid bullet lube and they would stick to it.you never saw any difference until after 200 yds on target,but we all want to do our best,I also tried using epoxy to keep them on the full distance but never grouped as well as ltting them fall off a clean based bullet.hope this helps if using a tumble type lube.

Just a thought, anyone got a box of 41 cal checks that they want to part with?? If so, please send me an e-mail or post here.

Thanks!

Bigbelly,

B: I have been playing with the igc too and have also to add; make sure that the bullet bases are clean, that way the checks don`t fall off at irregular intervals..

F: Yes. That consideration was not mentioned in the artical but it is important.

When I lube bullets prior to the seating operation I clean the base of each one by rubbing it over old terry cloth (worn out towel) to assure that no lube remains on the bases. Getting any under-bullet wad or IGC to drop off consistently is worth the extra procedure I think.

Good morning,
Forrest

Mike,

You've got mail.

Got some comin so i hope to get some results to post here soon.....

Someone else here offered me a box of checks and a bullet mold. I sent back a reply that i am interested just in case my e-mail got bounced.....

OK, WHAT GIVES?? I understand that these things are not sized BUT what is the trick to gettin them in the case straight?? I have no prob getting em in crooked, LOL!

I thought that i had the case belled enough but might not have. What is the trick???

flat side up ,put on top of case then bullet on top of check -hold with fingers then a short stroke on press just to seat check in straight, realign bullet then full stroke to set bullet and crimp.In 480 SRH i never could get consistant results at 50 yards with IGC,at 25 yards very good accuracy but at 50 no good,bullets had a tendency to spray